The concentration of nutrients entering coastal watersheds in southeast Alaska is in part controlled by the extent of glacial coverage in the river catchment area, according to research published online this week in Nature Geoscience. These rivers supply coastal ecosystems with nutrients and fresh water. Changing levels of glacial coverage in southeast Alaska could therefore potentially affect nutrient concentrations in nearby rivers and alter the nutrient dynamics of coastal ecosystems along the Gulf of Alaska.
Eran Hood and Durelle Scott sampled three adjacent watersheds along the Gulf of Alaska with differing levels of glacial coverage. They found that higher levels of glacial coverage were associated with increased phosphorous input to the rivers, whereas smaller glacial extent led to more organic matter entering the watershed. Areas of recent glacial retreat had temporarily increased levels of nitrogen, owing to the colonization of plants on the newly exposed terrain.